This invention relates to a brake control unit to be used in a brake system in a vehicle.
More particularly, the present invention relates to a brake control unit installed in a brake liquid supplying line extending from a master cylinder of a vehicle to a wheel cylinder and applied for an anti-lock control for the vehicle or the like.
As prior art of this kind of brake control unit, a brake liquid supplying line extending from a master cylinder M/C to a wheel cylinder W/C in an anti-lock control device will be described in reference to FIG.8.
In this figure, a hold valve 3a composed of a normally-opened solenoid valve is placed on a major liquid pressure line 2 extending from the master cylinder M/C connected to a brake pedal 1 to the wheel cylinder W/C. A bypassing liquid circuit 4 for bypassing this hold valve 3a is provided, and a check valve 5 for allowing only a liquid flow from the wheel cylinder W/C to the master cylinder M/C to be flowed in case that a liquid pressure of the wheel cylinder W/C is more than a predetermined value is placed on the bypassing liquid line 4.
On a return liquid line 6 extending from the aforesaid wheel cylinder W/C to the master cylinder M/C are placed a decay valve 3b composed of a normally-closed solenoid valve, an accumulator 8 and a pump 9 driven by a motor M, respectively.
With such a configuration as above, the hold valve 3a and the decay valve 3b are controlled for their opening or closing operation properly with a control part not shown, thereby a liquid pressure within the wheel cylinder W/C is controlled and then a lock of the wheels in case of braking the vehicle is prevented.
In case of a vehicle provided with a vehicle braking auxiliary mechanism such as the aforesaid anti-lock control device, it is a substantial problem to keep an assemblying space for these mechanisms and in case of either a vehicle or a small-sized vehicle having another electronic control mechanism already installed therein, it is sometimes found that there is no piping space for assemblying these mechanisms.
A technical concept for making a unit of valves to be used in the anti-lock mechanisms is also disclosed in the specification of U.S. Pat. No.3,538,947.
Accordingly, both a pump housing and a solenoid housing are provided for each of the solenoid valves and the anti-lock mechanism can be formed into a unit device. However, a structure in which the motor M is fixed to the pump housing becomes a structure in which a portion of the motor M is projected from the side surface of the pump housing and this shows a problem that a large-sized unit itself may not be avoided.